Allowed United States patent application of Francis L. Zrostlik, Ser. No. 351,776, filed Apr. 16, 1973, issued on Dec. 23, 1975 as U.S. Pat. No. 3,927,778 for "Tire Changing Apparatus" owned by applicant's assignee, discloses a simple and rugged tire gripping mechanism for a tire manipulating and tire changing apparatus. The tire gripping arms there disclosed are spaced apart and parallel, so that the tire gripping elements at the free ends of the arms are not aligned. The very large tires which such apparatus is designed to handle are difficult to manipulate at best; and it has been found that the lack of alignment between the tire gripping members increases the difficulty of handling a large tire properly.
The problem is particularly acute when a tire is to be picked up which is lying flat on a supporting surface. To do so, the tire gripping elements of the apparatus must both be in the same horizontal plane; and to get them in the same horizontal plane requires that the head on which the tire gripping mechanism is mounted be axially rotated, putting the parallel housings of the mechanism at an angle to the horizontal. It is difficult for an operator to judge the angle properly so that he knows when the tire gripping elements are in the same horizontal plane.